流动图书馆是一个图书漂流和借阅工具，旨在共享闲置图书，并链接趣味相投的小伙伴。那么流动图书馆小程序如何开发

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技术栈

小程序MINA框架： 一个响应的数据绑定框架。分为两块视图层(View)和逻辑层(App Service)

Flex：flex弹性布局

Express: http服务框架

websocket: 前后端消息的实时推送

mongoose: 操作mongodb数据库

pm2: 服务端使用pm2部署，常驻进程

代码结构

微信小程序中每个页面会有四个文件.js.json.wxml.wxss

js文件中是页面的逻辑，json文件是页面的一些配置，wxml是小程序的页面结构，wxss为页面的样式。

封装http请求

const request = (obj) => {

if(obj.header){

obj.header.sessionId = session.sessionId;

}else{

obj.header = { sessionId: session.sessionId};

}

wx.request(obj);

}

在请求头中手动加上sessionId,因为小程序没有cookie。

websocket

//连接websocket

wx.connectSocket({

url: 'wss://liudongtushuguan.cn/socketsessionId=' + session.sessionId,

});

wx.onSocketOpen(function(res){

});

wx.onSocketClose(function(res){

console.log('websocket closed');

});

wx.onSocketMessage(function(res){ //收到消息的回调

let msg = JSON.parse(res.data);

let msgs = that.data.borrowMessage;

msgs.unsShopfaft(msg);

that.setData({ borrowMessage: msgs});

});

//发送socket消息

let data = JSON.stringify({

targetId: bookData.ownerId,

nickName: APP.globalData.userInfo.nickName,

bookName: bookData.title,

time: new Date().toLocaleString(),

bookId: bookId,

wxNum: wxNum,

phoneNum: phoneNum,

msg: msg,

});

wx.sendSocketMessage({

data: data,

});

服务端

代码目录

Express框架实现http服务

const https = require('https');

const fs = require('fs');

const express = require('express')

const cookieParser = require('cookie-parser');

const bodyParser = require('body-parser');

const app = express();

const queryString = require('querystring');

const URL = require('url');

const socket = require('./service/socket');

const router = require('./routes/router').router;

//获取认证证书

var key = fs.readFileSync('./key/2_www.liudongtushuguan.cn.key');

var cert = fs.readFileSync('./key/1_www.liudongtushuguan.cn_bundle.crt');

var options = {

key : key,

cert : cert,

};

app.use(cookieParser());

app.use(bodyParser.json());

const httpsServer = https.createServer(options,app);

httpsServer.listen(443,() =>{

console.log('listening 443 port');

});

socket(httpsServer); //websocket

app.use(router);

小程序规定必须要用https协议。

websocket模块

const WebSocket = require('ws'); //使用ws模块

const queryString = require('querystring');

const URL = require('url');

const sessions = require('./session');

module.exports = (httpServer) => {

const wss = new WebSocket.Server({server : httpServer});

wss.on('connection',(ws, req) => {

let sessionId = queryString.parse(URL.parse(req.url).query).sessionId;

ws.id = sessionId;

ws.on('message' , (msg) => {

let msgObj = JSON.parse(msg);

if(sessions[msgObj.targetId]){

wss.clients.forEach((client) => {

if(client.id === msgObj.targetId){

let data = {

time : msgObj.time,

borrower :msgObj.nickName,

book :msgObj.bookName,

borrowerId : sessions[sessionId],

bookId : msgObj.bookId,

wxNum : msgObj.wxNum,

phoneNum : msgObj.phoneNum,

msg : msgObj.msg

};

client.send(JSON.stringify(data));

}

});

}

});

});

};

mongoose操作数据库

db.js:

const mongoose = require('mongoose');

mongoose.connect('mongodb://app:12345678@127.0.0.1/wxapp');

const connection = mongoose.connection;

connection.once('open', (err) => {

if(err){

console.log('Database connection failure');

}else{

console.log('Database opened');

}

});

connection.on('error',(err) => {

console.log('Mongoose connected error '+ err);

});

connection.on('disconnected', () => {

console.log('Mongoose disconnected');

});

module.exports = {

connection : connection,

mongoose : mongoose,

};

model.js:

const Schema = mongoose.Schema;

const UserSchema = new Schema({

onlyId : {type: String},

publishedBooks : {type: Array},

borrowedBooks : {type: Array},

borrowMessages : Array,

});

const BookSchma = new Schema({

isbn : String,

title : String,

press : String,

author : String,

rate : String,

tags : String,

image : String,

status : {type : Boolean,default : true},

ownerId : String,

owner : String,

ownerImage : String,

});

const userModel = mongoose.model('user' , UserSchema);

const bookModel = mongoose.model('book' , BookSchma);

module.exports = {

UserModel : userModel,

BookModel : bookModel,

}

获得微信用户的openId

小程序前端会请求微信服务器得到一个code, 将code发送给自己的服务器，然后自己的服务器给微信服务器发送请求，得到微信用户的唯一标识openId

const https = require('https');

const queryString = require('querystring');

const sessions = require('./session');

module.exports = (req, res, next) => {

let code = req.query.code;

let otherRes = res;

DATA.js_code = code;

OPTION.path = PATH + queryString.stringify(DATA);

let wxReq = https.request(OPTION, (res) => {

if(res.statusCode == 200){

let json = '';

res.on('data' , (data) => {

json+=data;

});

res.on('end' , () => {

json =JSON.parse(json);

let openId = json.openid;

sessions[openId] = openId;

otherRes.type('application/json');

otherRes.json({

data : {'sessionId' : openId},

});

otherRes.status(200);

});

}

});

wxReq.end();

};

使用pm2部署

安装pm2

npm install -g pm2

启动应用

pm2 start app.js

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